Topic: '77 CB400F restoration

[raisin75]

It's been a long time since I posted anything to this site. I purchased a '77 CB400F in October 2009 with 7400 miles on the ODO. I rebuilt it mechanically and put about 1200 miles on it. About 4.5 years ago, I completely stripped it to restore it cosmetically. I had not planned on it taking so long, but I really hate cosmetic work, and I don't have tons of money to throw at it. Anyway, on Monday I made some really good progress at finally starting to get the bike back together.

I've painted the frame and engine block/heads myself and had most of the other items powder coated, such as the engine covers, fenders, wheels, etc... I laced the wheels with new stainless spokes. My goal is to keep it mostly stock with the styling, but obviously custom on the colors with a black and gold theme. The tank will be black with gold racing stripes, including original decals from the blue bike. The side covers will be black with the gold 400FOUR.

I still have a fair amount of work left, but I'm getting excited, especially now that it's rolling again and thought I would share some pictures.

[raisin75]

And here are the current pictures.

[BomberMann650]

First cb I ever rode was a 400four. 
That started the 10 year quest for my own cb.

Nice bike.

[BobW]

Looks good.  Hope the rest of the build goes well.  I have a very original 77 cb400f and have been looking for a tank lid gasket (the black rubber gasket that fits on the bottom of the black lid that opens with the key to get to the gas cap, not looking for a gas cap gasket).  Looks like you've gone with a 75/76 tank with the chrome pop up gas cap (I like that one better too).  Do you still have the original tank and interested in selling the tank lid gasket (if it's in good condition)?  Many thanks!

[raisin75]

Bob, I am using the original tank. Maybe it's just not showing well in the pics. I don't remember the lid having a gasket when I got it. There is not one on it now. Now I have another item to investigate!

[BobW]

Honda PN 17522-377-720.  Keep me in mind should you find a couple and I'll do the same for you.

[beemerbum]

Bob, I am using the original tank. Maybe it's just not showing well in the pics. I don't remember the lid having a gasket when I got it. There is not one on it now. Now I have another item to investigate!

My '77 CB750K7 never had a gasket under the lid covering the gas cap. This bike has been in my family since new. These things never needed a gasket under the cover.

[raisin75]

It's been a few weeks since I posted. I don't work on the bike too often, but this weekend I had a few hours of wrenching. I was able to get all of the wiring complete from the back of the bike to the front. No headlight or signals installed yet, but all wiring is at least temporarily connected. I was able to get the valves adjusted and after a quick inspection of the carbs, put them back on the bike. Also, I filled the crankcase with fresh oil.

I kicked it over a few times with the kick-starter and everything sounded good. I connected jumper cables between my GL650 and the CB400F and turned on the key. Oil light on dash, instrument lights and rear taillight came on. Pressed the rear brake pedal and the brake light came on. So far, so good. I realized that all I needed was some fuel and see if it would fire, so I put the tank on and put a little gas in. Petcock on, fill the carb bowls and use the starter for the first try.

  First time she's been started in 4.5 years and it sounded like I'd never taken it apart. What a great feeling! I only let it run for a few seconds since I don't even have the exhaust attached yet, but it was running very well from what I could tell. Still lots of little details remaining, but it's feeling much closer now.

[503400f]

Awesome that it fired up!!!  Looking forward to more updates!

[raisin75]

A little more progress this weekend. I got the exhaust installed. I'm still unsure about the Triumph muffler. It will be ok for now, but I will probably go back to something similar to the factory muffler. I got the rear wheel and brakes finished and chain installed. And I finally got that stubborn airbox plenum attached properly. My new clutch cable came in the mail Saturday afternoon, too, so I installed that. Once the exhaust was on, I started it and let it run for a bit, without the muffler at first, of course.  Sounds great and runs great.

Since the rear brake was adjusted, I decided why not take it down the street. Just a couple hundred yards, but oh what fun!

I have a little oil coming from somewhere that I haven't had time to look into, but hoping it's just the oil pan gasket. Maybe I didn't get a good seal. I need to get the front brakes installed, turn signals and headlight installed, and chain guard installed. Oh, and a new battery. Then I'll start putting some miles on and working out the kinks... I'm going to spray the tank and side covers with Plasti-dip for now and get those painted properly this winter.

[MoMo]

Looks good.  Hope the rest of the build goes well.  I have a very original 77 cb400f and have been looking for a tank lid gasket (the black rubber gasket that fits on the bottom of the black lid that opens with the key to get to the gas cap, not looking for a gas cap gasket).  Looks like you've gone with a 75/76 tank with the chrome pop up gas cap (I like that one better too).  Do you still have the original tank and interested in selling the tank lid gasket (if it's in good condition)?  Many thanks!

Bob ,  I may have that part.  At work now, PM me as a reminder....Larry

[raisin75]

Getting very close on this little jewel. Last night I finished up the wiring for all the new signals and all the wiring inside the headlight bucket. Had to tweak the chain guard a little bit because it moved a lot when it got sand blasted prior to powder coating. I fired it up and did a couple of short test runs down the street before heading up to the gas station for a top off. Ran great other than a slight mid range flat spot. Nothing a little fine tuning won't fix.

Final item to install is front brakes. That will happen tomorrow. Going to put a coat of plasti-dip on the side covers and tank until winter, so I can ride it!

[Duanob]

Sweet project. Are going for a paint scheme similar to this:

[raisin75]

Actually, I found this CB900F after deciding on this paint scheme.

[raisin75]

I'm starting to get tired. Trying to wrench when I can and keep the family happy. I thought I was pretty much finished mechanically as of last night. I had to take the rear wheel back off because the bearing retainer was rotating in the hub. I used blue loctite, so hoping that takes care of that issue. On Sunday I rebuilt the front brake caliper and got the front brake all together and working very well.

I decided to take a chance this morning and head to work on the bike. Thankfully, I was less than a mile from home when it started sputtering.  I was able to hobble it back home, but I'm pretty sure it is fuel related. I probably have some trash in the tank that I didn't get out. The strainer that is attached to the petcock didn't come out when I drained the tank, and there's probably some trash that is restricting fuel flow. I DO have an inline fuel filter, and it looks clean, so probably above the petcock.

Oh well, I'm close. I just need to take a breath and get this done. Thankfully, my GL650 was sitting there, ready to go as usual!  What a great bike it is!

[flybox1]

Bearing retainers should be staked, so in the event that wheel has to come off, be sure and add 3-4 stakes to keep the retainer in place.
Revisit timing and carbs (clear tube test bowl fuel levels, idle plug chops to dial in IMS, etc.).  You'll get there!

[raisin75]

Last week I found the problem with the rear wheel bearing retainer. I missed a very important spacer when I put the wheel back together and it was causing the wheel to wobble. 
I was very lucky that I didn't ride much before I found the issue. I got a new retainer and new bearings and replaced them with the spacer and all is well.

I have put about 30 miles on it since, and haven't had any issues with it running. It has not missed a beat, so I'm not sure what happened the morning that it sputtered and quit.

Other than a few cosmetic items, it is ready to go.